Lecture 6: Quantitative Data Analysis

SOCB05 – Lecture 6 – June 13 2013
Quantitative Data Analysis
Quantitative Analysis
 Numerical representation and manipulation of observations for the purpose of
describing and explaining
Preparing the Data
 Generating Quantitative Data
o Respondents fill out survey/census questionnaires -> coding and codebook ->
Data Entry -> Data Cleaning -> Data Analysis -> Write a report
o SASS, SPSS, Stata: Writing a computer code to tell it how to analyse the
data. Need to input your own data.
o Quantifiable: Convert data into numeric form. Assign numbers to variables
and it’s various attributes.
 Example: Gender – Male=0 , Female=1
o Coding: Translate data into something that computers/statistical software can
recognize
 These numbers usually don’t mean anything, it’s just for
categorization purposes.
 If you do it to rank something, number it so it makes sense.
o Codebook: Document that describes the location of a variable within a
dataset and lists the codes assigned to the attributes composing those
variables
o Data Entry
 Data Entry specialists enter the data into statistical software or Excel
spreadsheet
 Optical scan sheets (Scantron)
 Sometimes it is part of the process of data collection.
 Once it’s put into the computer you can see basic information about
the variables.
o Data Cleaning
 No matter how careful someone is, there will always be mistakes.
Either by the researcher, during the entry, or during the study.
 Possible Code Cleaning
 The process of checking to see that only the codes assigned
to particular attributes appear in the data file.
 Make sure that only the numbers that are supposed to be
there, are there. Every respondent should fit into the numbers
chosen.
 Contingency Cleaning
 Checking that only those cases that should have data entered
for a particular variable do in fact have such data.
 Example: When you ask a question that has a second part to
it, only those that responded in a way to require the second
question.
 Example: Asking a question about how many children you
have given birth to, only women should answer it. No men
should have an answer for this.
o Analysing the Data
 Univariate Analysis  The examination of the distribution of cases of only one
variable
 Descriptive purposes only
 One-way frequency distributions
 Summarize distribution of a variable by reporting
the number of times each score of a variable
occurred (frequency)
 General rule for categories of frequency distribution:
o Exhaustive